1. Field of the Invention
The present invention relates to a method of simultaneously removing sulfur and mercury from a hydrocarbon material using a catalyst by means of a hydrotreating reaction.
2. Description of Related Art
Hydrocarbon materials, such as crude oil, natural gas and natural gas condensate as well as the gas, light naphtha, heavy naphtha, kerosene, light gas oil (LGO), heavy gas oil (HGO), atmospheric oil residues and the like produced therefrom, contain various amounts of sulfur, mercury, and sulfur and/or mercury compounds according to the origin and kind of material.
Damage, such as air pollution, acid rain and the like, may result when sulfur included in the hydrocarbon material is discharged into the air. Since sulfur poisons a cracking catalyst and a reforming catalyst in a large majority of petrochemical processes, sulfur must be removed before carrying out the petrochemical process. Particularly, since a reforming catalyst (a precious metal catalyst) is very sensitive to sulfur, the amount of sulfur included in a feed in a reforming process is generally limited to less than 1 ppm. For this reason, in order to remove sulfur from hydrocarbon, sulfur is reacted with hydrogen in the presence of a catalyst under a hydrogen atmosphere at high temperature and high pressure to be converted into hydrogen sulfide, which is then separated from the hydrocarbon using a separator.
Meanwhile, when mercury included in the hydrocarbon material is discharged into the air, environment and safety problems may be caused even if only a small amount of mercury is discharged. Further, when mercury comes into contact with a catalyst in a petrochemical process, mercury acts as a catalyst poisoning material, inactivating the catalyst, thereby damaging the petrochemical process. Particularly, since a reforming catalyst (a precious metal catalyst) is very sensitive to mercury, the amount of mercury included in a feed in a reforming process is generally limited to less than 1 ppb. For this reason, various methods for removing mercury from a hydrocarbon material have been developed.
Conventionally, there has been used a method of removing mercury, comprising the steps of: reacting hydrogen with a raw material containing mercury in the presence of a catalyst at a relatively high temperature; and trapping mercury from the reaction product using a trapping agent at a relatively low temperature. However, this method is problematic in that additional installation and operation costs are required because additional two-step processes must be conducted in order to remove mercury.